經濟批量排程問題(Economic Lot Scheduling Problem, ELSP)是單一機台在同一時間只能生產單一產品的多產品生產規劃問題。近年來由於環保意識的抬頭，許多國家都加以立法，要求企業承擔廢棄物、回收與再利用之責任，因此，本研究把回收與再利用的觀念加入傳統的經濟批量排程的問題內。考量在現實生活中，機台所生產出來的產品，未必皆能符合品管的標準，故本研究考慮生產系統同時具有操控和失控兩種模式。機器會因為長期使用而隨著指數分配在任意時間轉為失控模式，並可藉由維修由失控模式轉回操控模式，並分別考慮在不檢驗政策及定期檢驗政策下求解不完美系統之生產週期與每種產品之新品在生產週期中的製造次數使得單位期望總成本最小。並於性質分析中，證明出了在兩種政策下的經濟批量排程問題皆為一凸規劃問題。分別對兩種模式進行求解得到的解有下列性質（1）在定期檢驗政策中，製造期間之檢驗次數與產品的週期時間成正比，與新品之製造次數成反比；（2）於再製造期間之檢驗次數與產品的週期時間成正比。最後，於敏感度分析得知再製造整備成本、可用產品和尚不可使用回收產品的存貨持有成本、需求率與回收率對週期時間與總成本的影響程度較大。

Economic Lot Scheduling Problem（ELSP）is the problem which considers a single facility dedicated to the production of several different items. Recently, the rise of environmental consciousness, many countries made laws to require companies to take the responsibility of waste, recycling and reuse. So, this thesis considers the ELSP problem with remanufacturing. And in real life, facility produced products are not necessarily to conform quality control standards, so the process has two states: “in-control” and “out-of-control”. The facility may shift at a random time to out-of-control state with the exponential distributions. If the process is found to be in the out-of-control state, it can be restored it into in-control state. Two imperfect process models, one with inspection and the other with restoration, are constructed to minimize the total cost per unit time. The two ELSP models are shown to be convex programming problems, the cycle time and the number of new product produced for each product can be solved by differentiation. Furthermore, the models have the following properties. (1) In imperfect process with inspection and restoration, the inspection time during manufacturing period increase as the product cycle time increase, and as the number of new product produced decrease. (2) The inspected time during remanufacturing period increase as the product cycle time increase. Finally, the sensitivity analysis shows that setup costs for remanufacturing, holding cost for serviceable inventory, holding cost for recoverable inventory, demand rate and return rate have greater influence to the cycle time and total cost.

中文部分
蔣其軒 (2007)，「利用共同週期法求解不完美生產系統下可變動生產速率之經濟批量排程問題」，國立成功大學工業管理研究所碩士論文。
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